Odd Window Position Behavior with Dual Monitors

I've recently noticed an odd behavior with window positions with various apps (mostly Safari & Mail) when using dual monitors. I have a second Dell monitor connected via the Thunderbolt port on my iMac.

I've noticed various dialog boxes, like the bookmark "sheet" that appears when clicking the address bar will not be centered on the safari window. Typically restarting safari will resolve it, but once I move the window to my second screen the issue appears again.

With mail I've noticed when trying to drag and drop mail items to a specific folder I must offset my mouse left or right of the actual folder text by a few inches sometimes for the action to work correctly.

Again, restarting the app and leaving the app in the same position seems to resolve the issue, but once I move the app to the second screen this behavior appears.

I'm wondering if any one else has noticed this.

Update: I've reported this to APPLE via Bug Reporter... bugreport.apple.com

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